8. If direct digital control is NOT being used on the unit,
connect the 2 gray wires in the low voltage compart-
ment of the control box to the digital indicator wires
coming from the thermostat.
9. Filter Switch
If direct digital control is used on the unit, connect the
2 gray wires in the low voltage compartment of the
control box to the 10 and 11 pins of the direct digital
control.
Fan Switch
If direct digital control is used on the unit, connect
the 2 gray wires in the low voltage compartment of
the control box to the 8 and 9 pins of the direct digital
control.
10. Return power to unit.
11. To configure switch, perform the following:
Filter switch
Place the unit in Fan Only mode. The unit return air fil-
ter should be clean or new. Using a flat head screw-
driver, rotate the adjustment knob until the pressure switch
closes (see Fig. 1). Rotate the adjustment knob in the
same direction another
1
⁄
4
turn.
Fan Switch
Rotate the adjustment knob two full turns.
12. Reinstall filter access panel from Step 1.
OPERATION
When the pressure switch is set up as a filter switch, the
digital indicator light on the thermostat will be lit when the
filter is dirty and needs to be replaced. If direct digital con-
trols are used, the filter status (CLEAN/DIRTY) will be sent
over the communication bus.
When the pressure switch is set up as a fan switch, the
digital indicator light on the thermostat will be lit when the
indoor fan is operating. If the indoor fan is being told to op-
erate by the thermostat and the indicator light is not lit, serv-
ice the unit immediately. If direct digital controls are used,
the indoor fan operation status (ON/OFF) will be sent over
the communication bus.
Fig. 2 — Mounting Fan/Filter Status Switch
Copyright 1994 Carrier Corporation
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1
1
1
4
4
4
Tab
1a 1b 5a 5a 6a 6b
PC 111
Catalog No. 564-809
Form 48/50-28SI
Pg 2
9-94
Replaces: New
